One possible reason for transshipment is to change the means of transport during the journey (e.g., from ship transport to road transport), known as transloading. Another reason is to combine small shipments into a large shipment (consolidation), dividing the large shipment at the other end (deconsolidation). Transshipment usually takes place in transport hubs. Much international transshipment also takes place in designated customs areas, thus avoiding the need for customs checks or duties, otherwise a major hindrance for efficient transport.
An item handled (from the shipper's point of view) as a single movement is not generally considered transshipped, even if it changes from one mode of transport to another at several points. Previously, it was often not distinguished from transloading, since each leg of such a trip was typically handled by a different shipper.
Transshipment is normally fully legal and an everyday part of world trade. However, it can also be a method used to disguise intent, as is the case with illegal logging, smuggling, or grey-market goods.
The transshipment of containers at a container port or terminal can be defined as the number (or proportion) of containers, possibly expressed in TEU, of the total container flow that is handled at the port or terminal and, after temporary storage in the stack, transferred to another ship to reach their destinations. The exact definition of transshipment may differ between ports, mostly depending on the inclusion of inland water transport (barges operating on canals and rivers to the hinterland). The definition of transshipment may:
In both cases, a single, unique, transshipped container is counted twice in the port performance, since it is handled twice by the waterside cranes (separate unloading from arriving ship A, waiting in the stack, and loading onto departing ship B)...
At a break-of-gauge, cargo is transloaded from boxcars or covered goods wagons on one track to wagons on another track of a different rail gauge, or else containers are transloaded from flatcars on one track to flatcars on another track of a different gauge. Variable-gauge axles can eliminate this inconvenience.